The present invention relates to an exposure apparatus and a device manufacturing method used to manufacture a semiconductor element, liquid crystal display element, thin-film magnetic head, or the like, by lithography.
To manufacture a semiconductor element by lithography, an exposure apparatus which irradiates a mask having a transfer pattern formed on it with exposure light emitted from a light source to project the pattern onto a photosensitive member through a projection optical system is generally used.
To cope with an increase in view angle of a semiconductor element or the like, a scheme is conventionally used which performs exposure while synchronously scanning a mask and photosensitive member to project a transfer pattern in a region wider than the illumination region.
In recent years, the following method called stitching is used to realize a larger view angle (FIG. 3)
[Step 1] Exposure light is emitted from an exposure light source while synchronously scanning a mask and photosensitive member to perform exposure in an exposure region 31 by first scanning.
[Step 2] For second exposure, the photosensitive member is moved in a direction perpendicular to the scanning direction.
[Step 3] Exposure light is emitted from the exposure light source while synchronously scanning the mask and photosensitive member to perform exposure in a second exposure region 32 which is in contact with the first exposure region 31 by second scanning. The first and second exposure regions are connected by so-called stitching, and consequently, a large transfer pattern (a pattern that forms one electronic circuit) is transferred.
In the prior art, however, exposure unevenness may occur at the connection portion between the exposure region by the first scanning and that by the second scanning.
FIGS. 14A and 14B show exposure amount distributions on a cross section taken along a direction perpendicular to the scanning direction when exposure is performed on the basis of the conventional technique. Ideally, the connection portion has neither superposition nor gap. However, the ideal distribution cannot always be obtained because of, e.g., limited mechanical accuracy. FIG. 14A shows a state wherein an exposure superposed portion A1 is formed at the exposure connection portion between the exposure region by the first scanning and that by the second scanning. In this case, the exposure amount of the portion A1 is larger than that at the remaining positions. On the other hand, FIG. 14B shows a state wherein a portion A0 is present, where no exposure is obtained because of a gap formed at the exposure connection portion by exposure in the first scanning and that in the second scanning. In this case, the portion A0 has an exposure error.
It is an object of the present invention to further improve the above prior art and provide an exposure apparatus and device manufacturing method which can reduce any exposure unevenness at the connection portion between the exposure region by the first scanning and that by the second scanning by the stitching method.
In order to achieve the above object, according to the present invention, there is provided an exposure apparatus which has an illumination system for transferring a pattern formed on a master onto a photosensitive member by exposure light, a stop for setting an illumination region by the exposure light, and a mechanism for synchronously scanning the master and photosensitive member in predetermined scanning directions, and repeatedly executes exposure by synchronous scanning of the master and photosensitive member and relative movement of the photosensitive member in a direction crossing the scanning direction, thereby forming a transfer pattern with connected exposure regions on the photosensitive member, characterized by comprising a stop driving mechanism for performing exposure while driving the stop, for setting the illumination region in the direction perpendicular to the scanning direction, in the direction crossing the scanning direction in a plane perpendicular to the optical axis of the illumination system upon synchronously scanning the master and photosensitive member.
According to the present invention, there may also be provided an exposure apparatus which has an illumination system for transferring a pattern formed on a master onto a photosensitive member by exposure light, a stop for setting an illumination region by the exposure light, and a mechanism for moving the photosensitive member in a predetermined direction, and repeatedly executes static full plate exposure and relative movement of the photosensitive member, thereby forming a transfer pattern with connected exposure regions on the photosensitive member, characterized by comprising a stop driving mechanism for performing exposure while driving the stop in a plane perpendicular to the optical axis of the illumination system in static full plate exposure. According to the present invention, there is also provided a device manufacturing method characterized by comprising the step of controlling exposure to reduce an exposure amount unevenness at a connection portion between first and second regions in forming a transfer pattern having the first and second regions connected by the first step of exposing and transferring the pattern in the first region on a photosensitive member and the second step of exposing and transferring the pattern in the second region in contact with the first region.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.